1. Field of the Invention
This invention relates to belt aligning and tracking rollers and more particularly to rollers having improved ribbing configuration providing increased traction.
2. Description of the Prior Art
Tracking and aligning of strips, belts and webbing material on rollers or pulleys have been universal problems. Crowned or tapered rollers are employed in an attempt to prevent the webbing from running sideways. Wormed surface rollers are also used with either inwardly and/or outwardly tending spiral ridges for centering and/or stretching the webbing material relative to the rollers. The narrow ridges, however, tend to lift the webbing, decreasing the contact area with the roller and thus decreasing the traction.
Heretofore, the problem has been approached in several different ways. One approach is to increase the number of narrow ridges on the roller to increase the surface area of contact. This increases the number of ridges per inch, or the pitch, decreasing the ridge angle. The decreased angle, however, decreases the tracking efficiency of the roller.
Another approach increases the coefficient of friction of the ridges themselves. Such an approach is disclosed in my earlier U.S. Pat. No. 3,812,732. In this disclosure tooth-like barbs are cut in the ridges. The difficulty with this approach is that it is not effective for all types of material. Another disadvantage is that the teeth tend to wear relatively rapidly.